Also known as: comity · comity of nations
Written by attorneys · grounded in primary & secondary sources — see below
A principle of deference under which courts of one sovereign refrain from exercising jurisdiction or granting relief that would interfere with the laws or judicial proceedings of another sovereign. The principle rests on mutual respect among independent legal systems and promotes orderly relations between them. It applies both to foreign nations and to coordinate sovereigns within a federal system.
State prosecutors in State A charge Ines Ibarra with fraud arising from a local construction contract. While the state case is pending, Ibarra files a federal suit seeking to enjoin the prosecution on due-process grounds. The federal court declines to issue the injunction because the state proceeding is ongoing and no bad-faith or harassment appears.
Foreign plaintiffs sue Daimler AG in California for events that occurred entirely in Argentina. The court refuses to assert general jurisdiction over the German parent company, citing the transnational setting and the need to avoid friction with foreign sovereigns.
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A State A court enters a default judgment against a nonresident whose only contact with the state is receipt of a mailed summons. When the plaintiff seeks enforcement in State B, the second court refuses recognition because the first judgment exceeded the territorial reach of State A authority.
After a federal diversity claim is dismissed, only state-law construction-defect claims between non-diverse parties remain. The district court relinquishes the remaining claims so that a state court can interpret an untested state statute without federal interference.
Nigerian plaintiffs sue a foreign oil company in U.S. court for conduct that occurred entirely on Nigerian soil. The court dismisses the claims, noting that adjudicating foreign conduct would risk international discord and should be left to the courts of the nation where the events took place.
A federal consent decree resolves employment-discrimination claims against a city. Nonparty employees later sue in state court seeking different relief. The state court proceeds because the federal decree did not purport to bind absent parties and comity favors allowing the state forum to adjudicate its own citizens' claims.
Federal courts generally abstain from enjoining ongoing state criminal proceedings absent extraordinary circumstances such as bad-faith prosecution, harassment, or a flagrantly unconstitutional statute. The principle rests on mutual respect between sovereigns and prevents federal interference with state enforcement of its own laws.
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Courts consider the transnational context and the risk of international friction when deciding whether to assert expansive general jurisdiction over foreign defendants. Deference to foreign sovereigns counsels against jurisdiction that reaches conduct having no connection to the forum.
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No. Once a sister state renders a final judgment with proper jurisdiction, other states must recognize and enforce it even if they disagree with the legal analysis. Collateral attack is limited to narrow grounds such as lack of jurisdiction.
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…an elementary principle, that the laws of one State have no operation outside of its territory, except so far as is allowed by comity; and that no tribunal established by it can extend its process beyond that territory so as to subject either persons or property to its decisions. "Any exertion of authority of this sort…